US 2006/0067233 A1 · Network device with traffic shaping functions and bandwidth control method using leaky bucket algorithm

Abstract

A network device with bandwidth usage control functions using a leaky bucket algorithm to provide a traffic service conforming to given user parameters. A leaky bucket counter produces a new leaky-bucket (LB) count at predetermined cell slot intervals by adding an output rate parameter to the previous count, and then by subtracting therefrom a full rate parameter if a cell output request signal is active. An upper limit calculator determines an upper limit for such LB count values, and a count modifier applies this upper limit, thereby producing a modified LB count. When the modified LB count from the count modifier equals or exceeds an output reference value, a comparator activates an output timing signal, which permits transmission of a pending cell in a buffer.

Claims18

Dependent claims

A network device having bandwidth control functions to transport cells, comprising:

(a) a cell buffer that stores received cells and outputs one of the stored cells each time a cell output request signal becomes active;
(b) a cell count manager that provides a stored cell count indicating the number of cells stored in said cell buffer;
(c) a leaky bucket controller that controls bandwidth usage at a source end by using a leaky bucket algorithm, comprising:
a leaky bucket counter that calculates a leaky bucket (LB) count at predetermined cell slot intervals by adding an output rate parameter to a modified LB count, and by subtracting therefrom a full rate parameter if the cell output request signal is active,
an upper limit calculator that determines an upper limit for the LB count,
a count modifier that produces a new value of the modified LB count by limiting the LB count not to exceed the upper limit, and
a comparator that activates an output timing signal when the modified LB count from the count modifier equals or exceeds an output reference value;
and
(d) a cell output enable logic that activates the cell output request signal when the output timing signal is active and when the stored cell count is one or more.

6 more elements

A network device having bandwidth control functions to transport cells, comprising:

(a) a cell buffer that stores received cells and outputs one of the stored cells each time a cell output request signal becomes active;
(b) a cell count manager that provides a stored cell count indicating the number of cells stored in said cell buffer;
(c) a leaky bucket controller that controls bandwidth usage at a source end by using a leaky bucket algorithm, comprising:
a leaky bucket counter that calculates a leaky-bucket (LB) count at predetermined cell slot intervals by adding an output rate parameter to a modified LB count, and by subtracting therefrom a full rate parameter if the cell output request signal is active,
a count modifier that produces a new value of the modified LB count by limiting the LB count not to exceed an output reference value when the LB count has reached the output reference value and when the stored cell count is zero, and
a comparator that activates an output timing signal when the modified LB count from the count modifier equals or exceeds the output reference value;
and
(d) a cell output enable logic that activates the cell output request signal when the output timing signal is active and when the stored cell count is one or more.

5 more elements

A network device having bandwidth control functions to transport cells, comprising:

(a) a cell buffer that stores received cells and outputs one of the stored cells each time a cell output request signal becomes active;
(b) a cell count manager that provides a stored cell count indicating the number of cells stored in said cell buffer;
(c) a leaky bucket controller that controls bandwidth usage at a source end by using a leaky bucket algorithm, comprising:
a leaky bucket counter that calculates a leaky-bucket (LB) count at predetermined cell slot intervals by adding an output rate parameter to a modified LB count, and by subtracting therefrom a full rate parameter if the cell output request signal is active,
an upper limit calculator that determines an upper limit for the LB count,
a first count modifier that produces a first modified LB count by limiting the LB count not to exceed the upper limit,
a second count modifier that produces a second modified LB count by limiting the LB count not to exceed an output reference value when the LB count has reached the output reference value and when the stored cell count is zero,
a selector that selects either the first modified LB count or the second modified LB count, depending on a given service mode, and
a comparator that activates an output timing signal when the first or second modified LB count selected by said selector equals or exceeds the output reference value;
and
(d) a cell output enable logic that activates the cell output request signal when the output timing signal is active and when the stored cell count is one or more.

8 more elements

A method for controlling bandwidth usage at a source end by using a leaky bucket algorithm, comprising the steps of:

(a) calculating a leaky-bucket (LB) count at predetermined cell slot intervals by adding an output rate parameter to a modified LB count, and by subtracting therefrom a full rate parameter if a cell output request signal is active,
(b) setting at least one of maximum burst size, cell delay variation tolerance, and sustainable cell rate;
(c) calculating an upper limit for the LB count when the maximum burst size or cell delay variation tolerance is set at said setting step (b);
(d) producing a first modified LB count by limiting the LB count not to exceed the upper limit;
(e) comparing the LB count with an output reference value when the sustainable cell rate is set at said setting step (b);
(f) producing a second modified LB count by limiting the LB count not to exceed the output reference value when the LB count has reached the output reference value and when the stored cell count is zero;
and
(g) outputting a cell when the first or second modified LB count equals or exceeds the output reference value.

5 more elements

Dependencies are inferred from the claim text.

Network device with traffic shaping functions and bandwidth control method using leaky bucket algorithm

Life of this patent

Network device with traffic shaping functions and bandwidth control method using leaky bucket algorithm

Life of this patent

Abstract

Claims18